Linux: Use After Free
CVE-2022-49413 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions da9f3025d595956410ceaab2bea01980d7775948, b06691af08b41dfd81052a3362514d9827b44bb1, e8821f45612f2e6d9adb9c6ba0fb4184f57692aa as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to da9f3025d595956410ceaab2bea01980d7775948 or b06691af08b41dfd81052a3362514d9827b44bb1 or e8821f45612f2e6d9adb9c6ba0fb4184f57692aa or d9165200c5627a2cf4408eefabdf0058bdf95e1a, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.198 or 5.10.121 or 5.15.46 or 5.17.14, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, da9f3025d595956410ceaab2bea01980d7775948; e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, b06691af08b41dfd81052a3362514d9827b44bb1; e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, e8821f45612f2e6d9adb9c6ba0fb4184f57692aa; e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, d9165200c5627a2cf4408eefabdf0058bdf95e1a; e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, 2a1077f17169a6059992a0bbdb330e0abad1e6d9; e21b7a0b988772e82e7147e1c659a5afe2ae003c up to, but not including, ea591cd4eb270393810e7be01feb8fde6a34fbbe; 4.12 | da9f3025d595956410ceaab2bea01980d7775948, b06691af08b41dfd81052a3362514d9827b44bb1, e8821f45612f2e6d9adb9c6ba0fb4184f57692aa, d9165200c5627a2cf4408eefabdf0058bdf95e1a, 2a1077f17169a6059992a0bbdb330e0abad1e6d9, ea591cd4eb270393810e7be01feb8fde6a34fbbe |
| Linux | Linux Kernel | 4.12 up to, but not including, 5.4.198; 5.5 up to, but not including, 5.10.121; 5.11 up to, but not including, 5.15.46; 5.16 up to, but not including, 5.17.14; 5.18 up to, but not including, 5.18.3 | 5.4.198, 5.10.121, 5.15.46, 5.17.14, 5.18.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: bfq: Update cgroup information before merging bio When the process is migrated to a different cgroup (or in case of writeback just starts submitting bios associated with a different cgroup) bfq_merge_bio() can operate with stale cgroup information in bic. Thus the bio can be merged to a request from a different cgroup or it can result in merging of bfqqs for different cgroups or bfqqs of already dead cgroups and causing possible use-after-free issues. Fix the problem by updating cgroup information in bfq_merge_bio().
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/2a1077f17169a6059992a0bbdb330e0abad1e6d9
- git.kernel.org/stable/c/b06691af08b41dfd81052a3362514d9827b44bb1
- git.kernel.org/stable/c/d9165200c5627a2cf4408eefabdf0058bdf95e1a
- git.kernel.org/stable/c/da9f3025d595956410ceaab2bea01980d7775948
- git.kernel.org/stable/c/e8821f45612f2e6d9adb9c6ba0fb4184f57692aa
- git.kernel.org/stable/c/ea591cd4eb270393810e7be01feb8fde6a34fbbe
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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